


Cold War Pacts Can Get Rather Hot

by guilty_pleasures_abound



Series: First of His Kind [1]
Category: Invader Zim
Genre: Adult Dib (Invader Zim), Alien Biology, Alien Sex, First Time, Frenemies, Hermaphrodites, M/M, Oral Sex, Plot What Plot/Porn Without Plot, Rough Sex, Unsafe Sex, Vaginal Sex
Language: English
Status: Completed
Published: 2020-01-08
Updated: 2020-01-08
Packaged: 2021-02-18 23:36:21
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 5,730
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22168321
Author URL: https://archiveofourown.org/users/guilty_pleasures_abound/pseuds/guilty_pleasures_abound
Summary: Having sex with his frenemy was not what Dib expected to do with his day. It wasn't an opportunity he was going to turn down, though.
Relationships: Dib/Zim (Invader Zim)
Series: First of His Kind [1]
Series URL: https://archiveofourown.org/series/1611292
Comments: 16
Kudos: 401





	Cold War Pacts Can Get Rather Hot

**Author's Note:**

> Is Dib overconfident in this? Maybe. Do I think his rabid curiosity about Zim's biology justifies it? I think so. Hopefully you do too.

Zim was shaking, and Dib was not afraid to admit it was a good look on him.

So was the view of him lying on his back on the couch, leggings tangled around one ankle and tunic hiked up under his arms; more exposed than he had ever allowed Dib to see him before, more exposed than Dib ever thought he would see—unless, of course, he had gotten his way as a kid and strapped Zim to an exam table for dissection.

He still wouldn't mind strapping Zim to an exam table, if he was being honest with himself, only now the idea of cutting into him to see how the Irken worked was less appealing than strapping him down and driving him a bit crazy with sensation; trading a scalpel for something like an ice cube or hot wax just to see how he would squirm.

Though truthfully, it didn't take much to make the little alien squirm—case and point, the way he did just that when Dib put his mouth to Zim's abdomen, pressing a hot, open-mouthed kiss there while his hands ran up and down the underside of Zim's thighs. It was a little uncomfortable to do with the way he was sitting; feet on the floor, twisting to lean over Zim, but it was a small price to pay for the opportunity to get this close, explore this thoroughly.

The little squeak Zim gave in response, the way his fingers gripped Dib's hair, the way his muscles tightened under Dib's hands and mouth; it made Dib shiver, so achingly hard already and Zim had barely touched him. He didn't need to, really, Dib so stupidly, _ridiculously_ turned on by him when the Irken wasn't even trying, so seeing _this_ —having _Zim_ panting and squirming and whimpering under him—there was no way Dib could do anything but be hopelessly aroused.

That, at least, seemed to be a shared experience; Zim's... (cock? What was the Irken word for penis anyway?) undeniably reacting to the way Dib was touching him. There was also no denying that Dib was completely fascinated by it; the pink, lightly twitching organ emerging from a slit in Zim's body, looking soft and almost shiny. And now that Zim's pants were out of the way, there was no way Dib wasn't touching it.

"Sh, sh, sh," Dib murmured when Zim gasped and arched, Dib's free hand splayed flat on Zim's abdomen while his other hand wrapped exploringly around Zim's dick.

It _was_ soft; the closest texture comparison Dib could think of was the inside of his own mouth—like what it felt like to rub the tip of his finger against the inside of his cheek. It was slick like the inside of his mouth too, Zim's body seeming to produce its own lubrication naturally. Dib wanted to taste it.

First he explored a little more, stroking from base to tip, unabashedly staring, his lips slightly parted. It was bigger than he thought it would be; probably somewhere between four and five inches long at a guess, maybe two inches in diameter at the base, getting thinner as it tapered upward, ending at the flat, inch wide tip. It looked proportionally large in comparison to the rest of Zim’s 4’10” frame, and he couldn’t help but wonder how Zim stacked up to others of his species when it came to this.

"Oh," he breathed a moment later, watching in amazement when Zim twitched and gasped again, his strange, slippery cock actually _flexing_ and _curling_ into the grip of Dib's hand, almost prehensile. "Do you have control of this?"

Zim gave a fevered shake of his head, his eyes scrunched closed and his antennae twitching almost as much as his cock.

"Amazing," Dib murmured in awe, gaze dropping back down to Zim's organ, giving another exploratory stroke along the length. "Fucking... amazing."

Zim whimpered, his petite hands squeezing against the back of Dib's head, making the human smile. Zim was fucking putty after a genuine compliment, it really was an extraordinary thing to witness. He marched around with so much bravado, his attitude that of someone who thought they should rule the world (and oh he had tried), but his soul-deep desire for external validation had become abundantly clear to Dib in recent years.

"One of these days," Dib said with a glance up, "you're going to walk me through your whole anatomy."

Zim's haze of arousal was clearly not enough to dampen his brattiness, his scoff and sharp tug at Dib's hair saying exactly how he felt about that idea. "You wish, Dib-stink."

Dib narrowed his eyes at the challenge; he'd get his way, sooner or later, Zim's resistance bound to melt away with the right persistence. There were benefits to this truce of theirs, Dib had to admit. It certainly made investigating Zim easier when they weren’t actively trying to kill each other. "I _know_ , Space Boy."

Another stroke of his hand cut off any annoyed retort Zim might have thrown at him, Dib’s gaze returning to the soft pink flesh in his palm. He observed the flat, almost heart-shaped tip, which had an opening a little smaller than the diameter of a nickel that was most definitely leaking either pre-cum or lubrication, along with a scent that Dib could only compare to molasses; a cloying, almost sickeningly sweet tang that lingered in the back of his nose, and Dib finally gave in to his impulse to taste—touching the tip of his tongue to the opening of Zim's cock.

He had _never_ heard Zim make a noise like the one that erupted from his throat then, his legs snapping closed around Dib's head and his hips jerking like he'd been electric shocked. It just made Dib all the more curious, exploring the shape of Zim's cock with his tongue as his brain tried to categorize the way he tasted. It was like eating sour candy; a sharp, nearly metallic tartness that hit his tongue first, then a heady sweetness that chased on its heels and made Dib's mouth and eyes water.

Zim gasped a word that Dib didn't understand, his dick curling and wiggling against Dib's tongue like it was seeking something. Dib had a feeling he knew what; his own dick was throbbing and aching behind the zipper of his jeans, desperate for something, _anything_ to alleviate that ache. Instead he slid the flat of his tongue up the underside of Zim's cock until he reached the tip again, dipping his tongue into the opening to the sound of another Irken curse from Zim.

"You _wretched_ —" Zim growled, fingers pulling sharply on Dib's hair in dissatisfaction, admittedly making Dib smirk. "You wretched, teasing, horrible—"

Dib shouldn't have rewarded him, really, but wrapping his lips around the tip of Zim's cock to shut him up was an amusing opportunity he couldn't pass by. Even more exhilarating when Zim's cock wiggled, pressing against his tongue with eagerness.

His victorious feeling was short-lived when Zim's fingers tightened again, his hands suddenly yanking Dib down _hard_ , forcing himself into Dib's mouth with all the finesse of a hurricane ripping through a trailer park.

Naturally, Dib gagged and coughed, bracing his hands on Zim's hips to give him the leverage to pull back, no matter how hard Zim's legs and hands tried to keep him down.

 _"Zim!"_ he rasped in annoyance, digging his fingers into the Irken's skinny hips. "I can't do this if you choke me!"

"Then cease your teasing, Dib-stink!" Zim snapped back at him, hiking up onto one elbow to glare at Dib's face, still trapped tight between Zim's thighs. "I have not shed my clothing for you to leave me unsatisfied!"

"You haven't given me a _chance_ to satisfy you, you space bug," Dib retorted, determinedly ignoring the way his face was heating up. "Haven't you ever heard of foreplay?"

"No," Zim said flatly, eyes narrowed in annoyance. It was not a helpful answer.

"For fuck's... ugh, just shut up, Zim."

“I will not be silenced, Dib-thing! You dare—!”

Distracting Zim when he was gearing up to rant was a talent Dib had learned through a lot of trial and error, and he was always exploring new methods; as it turned out, taking Zim’s dick back into his mouth was one of the more efficient ones—amusing, even, his words dying and sputtering with a strangled shout. It had the added bonus of being just so goddamn _fascinating_ , the hot organ twitching furiously at the stimulation and the head pressing itself firmly against Dib’s tongue. It made Dib suck experimentally, allowing it to slide a little deeper into his mouth, while above him, Zim seemed to be losing his mind.

It was a stroke to his ego, to say the least; the sound of what Dib could only assume were Irken curses muffled slightly by the way Zim’s thighs were pressing against the sides of his head, covering his ears. He smirked around his mouthful of Zim’s flesh, hands shifting from Zim’s hips to his knees, coaxing them apart slightly to give himself more room to work.

He almost wished he was taking notes; or maybe recording, so he could go back later and catalogue Zim’s reactions. He was already trying to memorize the way Zim’s gloved hands clenched in his hair, how the intensity of the suction of his mouth and the movement of his tongue was making Zim arch and gasp.

A particularly vicious tug at his hair made Dib wince and back off, Zim's cock sliding out of his mouth with a wet sound.

"I hate you," Zim hissed angrily, his dick squirming and curling from the loss of stimulation, and Dib almost felt a little bad for it.

"Stop trying to rip my scalp off, then," he replied, shaking his head a little to emphasize his point. To his credit, Zim's grip did lessen, but his annoyed huff was loud and exaggerated.

"Delicate worm baby," he growled.

"Yeah?" Dib raised an eyebrow. "Want me to yank on your antennae, see how it feels?"

"Try it, and I liquify you."

"Exactly."

Zim growled and grumbled, his knee knocking against the side of Dib's head; not _hard_ , it was clear he wasn't trying to _hurt_ , but most certainly intending to be annoying.

"Continue!" he ordered, ignoring Dib's "hey!" of indignation. "Or I'll turn you inside out!"

"Love to see you try, Space Boy." Dib nipped Zim's thigh when he tried to knock his knee against Dib's head again, the Irken gasping and leg spasming at the sink of Dib's teeth.

"Wretched worm-filth!" He growled, heel impacting against Dib's shoulder in a sharp kick that made Dib grunt. "Keep your teeth from my flesh or I'm ripping them out!"

"Then stop trying to hit my head!"

"It's so _ginormous_ I don't see how that's possible," Zim sneered, finally releasing Dib's hair to hike back up onto both elbows this time in order to give Dib a proper taunt. "Frankly I'm surprised you can fit down there at all, Dib-stink."

It never failed, Zim always found a way to slip in some insult about Dib's head.

"You really want to make fun of me when I've got my teeth this close to your junk?" he challenged.

Zim kicked him again. "Do not call my splook 'junk' you filthy earth pig!"

Dib growled, gripping Zim's ankles and pinning them down to the couch cushions to keep him from kicking again. At least he knew the Irken term for penis now.

"Stop. Kicking. Me."

It turned into a staredown, glaring and fuming at each other for a solid thirty seconds, until suddenly Zim's hands shot up, gripping the lapels of Dib's coat and yanking him down, putting their faces a scant few inches from each other.

"Then _satisfy me."_

They glared some more, Dib trying to ignore the heat in his belly from the intimacy and intensity of their proximity.

"Say 'please' for once in your life and maybe I will."

"Feh!" Zim huffed. "Why would I ever do that?"

Now that the idea was planted in Dib's head, it was suddenly all he wanted; his brain racing with possibilities on how to get that simple word from Zim's mouth.

"Because, Zim—" He slowly leaned further in, forcing the Irken to either lay back or bump heads with him; Zim chose to lay back. "—I'm not getting you off without hearing it."

Zim's antennae flicked back, eyes narrowed and a scowl on his lips. _"You're lying!"_

"Not lying." Dib wanted to kiss him. Zim's mouth was so close, the tension between them wound tight. "Say please."

"Absolutely not."

He didn't kiss him, but he let go of one of Zim's ankles to hook his thumb under Zim's chin, fingers curled against his cheek as he tilted his head back.

"What...?"

Dib pressed his mouth to Zim's neck, feeling the alien shiver as he drew his lips along his thin throat. He was tempted to bite, the idea of giving Zim a hickey strongly tempting, but refrained. Maybe he could get away with that later, but it wouldn't do him any favors at the moment. Instead he just kissed, for the experience of cataloging the texture of Zim's skin as much as to hear him squeak and pant.

He made his way down to the base of his neck, stopped from reaching any more skin by the edge of Zim's tunic, so he reversed course, making his way back up.

"Say please, Zim," Dib muttered, parting his lips against Zim's skin, mouthing along the soft flesh just under his jaw.

Zim gasped, his hands releasing Dib's coat to sink into his hair again, holding tight and keeping Dib close, even as he shook his head. "No."

Zim's hands on his head suddenly made him curious; he had threatened to pull Zim's antennae in retaliation before, but actually stimulating them...

His hand left Zim's chin, cupping the side of his head gently before moving slowly upwards, distracting him with a soft suck to his neck until his fingers found the base of an antenna.

Zim's full-body shiver and gasp was way hotter than it had any right to be, solidifying Dib's theory that the appendages were sensitive; he played gently, rubbing the slender stalk between his first finger and thumb at the base before slowly working his way up.

"Guuuggghhh _I hate you,"_ Zim's voice fucking _wavered,_ breathless and about two octaves higher than usual, and Dib smirked as he switched to the other side of Zim's neck, continuing to stroke gently along his antenna.

The moment Dib released Zim’s other ankle in order to stroke both antennae at the same time, Zim was hooking his legs around Dib’s waist, locking his ankles across Dib’s back and grinding up against his belly. Dib let him, too interested in lightly sucking at a point on Zim’s neck that was making him whine and squirm.

“Say please, Zim,” he whispered again, cupping either side of Zim’s head as his finger and thumb on each hand massaged at the base of his antenna, which seemed to be the most sensitive part.

“I hate you,” Zim repeated in a breathless rasp, squirming and squeezing Dib’s waist with his legs, his cock writhing and twitching between them. _“Please_ , you wretched, horrible boy-human.”

One had to take the salty with the sweet when it came to Zim, so Dib easily rolled with the insults wedged around the “please.” He was used to it.

“Good boy,” Dib murmured, the way Zim shivered and squeezed him at the praise not going unnoticed. “See? Not so hard to say.”

“Shut _up,_ ” Zim growled. “Fulfill your promise.”

Most of the time, he would have no problem disregarding a promise he had made to Zim; after all, the fate of the planet was more important than the integrity of keeping a promise to an evil invader. The fate of the planet wasn’t in his hands today, though; today it was just Zim, and the hot, terrible pull between them that Dib wished he could deny.

He leaned back a bit, ignoring the way Zim whimpered and tried to keep him close with his hands.

“I’ve got you, Space Boy,” he muttered, releasing one of Zim’s antennae to slide his palm down, petting over his chest and belly on the way down to the flesh between his legs.

Zim’s cock squirmed and curled into the grip of his hand, so slippery now that the front of Dib’s shirt was wet, the natural lubrication shiny and slick in Dib’s palm. He took that as a good sign, especially with the way Zim was whimpering and writhing, hands shifting to Dib’s shoulders and clenching the fabric as his legs continued to squeeze Dib’s waist.

“Let me see it,” Dib panted, drawing Zim’s gaze to his face. “Show me.”

He realized he had no clue what to expect; he could make the reasonable assumption that Zim’s orgasm was similar to Dib’s, based on the fact that he seemed to have a sexual organ that was responding to the stimuli of being touched and stroked. But could he be _certain_ that the end result was going to be the same? Technically no, and the possibility intrigued him.

He stroked his hand quickly, squeezing the pulsing, wiggling flesh in his hand as Zim’s eyes slipped closed, moaning and whining noisily until he arched, antennae twitching like mad and whole body trembling. Dib gasped, suddenly finding himself with a palm full of a clear, thin fluid that had to be Zim’s ejeculate. Distantly, he wished he had a microscope to analyze it.

He wished he had a stopwatch too; Zim’s orgasm drawing out far longer than a human’s, close to a full minute for sure, spurts of cum pulsing from his cock every handful of seconds. It was a fucking _mess_ , liquid dripping from between Dib’s fingers, running down Zim’s sides and staining the fabric of the couch. The poor furniture would definitely need a cleaning before GIR could use it again.

Dib swallowed hard as he watched, not letting up the strokes of his hand until Zim went limp, panting hard and trembling from head to toe.

“Extraordinary,” he breathed without meaning to, fingers trailing gently down Zim’s shaft, then tracing the slit his _splook_ , as Zim called it, emerged from; curious about any other functions it might have, how far back inside his body it went, if it was controlled by Zim’s PAK or his organic brain.

Zim’s antennae twitched some more when Dib followed the edge of his slit down and behind his cock, wondering if there were any sort of external testes that he hadn’t noticed. He didn’t find any, but he found something else instead, that immediately sent his brain into a curious overdrive.

The skin was tight around most of Zim’s protruding cock, pulled back to allow the organ to emerge, but here… here the slit went further back than Dib anticipated, the skin wet and pliable. Dib found, after a moment of soft, exploratory petting, that it parted to allow his fingers entry into Zim’s body.

The moment the tip of his finger breached the slippery flesh, Zim spasmed with a cry, eyes flying open and heels scrambling against Dib’s sides.

“What— _what_ ,” Zim gasped, eyes widening with shock, meeting Dib’s surprised, curious gaze with an edge of franticness.

“What?” Dib echoed, withdrawing his finger but not moving his hand, returning to petting against the outside of this newly discovered opening. “What is this?”

Zim shook his head, eyes squeezing closed again and fingers clenching and twisting the fabric of Dib’s coat.

Since an answer from Zim didn’t seem to be forthcoming, Dib decided to explore; sliding the tip of one finger back inside, pressing a little further this time, rubbing cautiously but curiously at the hot, slick walls of Zim’s channel.

It occurred to him that this could be the Irken’s version of an asshole, which didn’t gross him out the way it might have a few years ago. Discovering porn had kind of taken the ick factor out of that equation when it came to the idea of anal exploration. It was curious if so; the same lubrication that oozed from Zim’s cock seemed to be here too, making it laughably easy for Dib’s finger to slide in all the way to the last knuckle, the muscles around his digit squeezing and fluttering at his intrusion. All the while he watched Zim’s face, watching the play of emotions that were flicking over the alien’s features. He didn’t seem to be in pain, but he was certainly experiencing a sense of shock mixed with pleasure that had definitely caught him off guard.

Another spill of Irken language fell out of his mouth when Dib curled his finger, rubbing exploringly at his insides and seemingly finding a sweet spot that made Zim lose his breath. It made Dib moan, arousal punching him in the gut; fuck he was so _hard_ , he couldn’t believe he had gotten so distracted by his fascination with Zim that he hadn’t even unzipped his jeans yet.

Part of him wanted to at least palm himself through the fabric, get a little bit of relief from the pounding, insistent pressure in his pelvis, but he refrained; the risk of coming in his pants too annoyingly high. If he was going to come today, it was not going to be in his underwear, dammit.

Another finger into Zim’s body and the Irken cried out, one of his hands releasing Dib’s coat to pound his fist into Dib’s shoulder, making Dib wince and scowl at him as he mercilessly rubbed that sweet spot he’d found in retaliation. Another hit to his shoulder and Dib released his remaining hold on Zim's antenna and leaned back, out of Zim’s reach but not letting up on this new stimulation between his legs.

It also gave him a chance to look at Zim’s dick, the organ several shades darker and drooling again, making even more of a mess of Zim’s abdomen and making Dib’s cock pound more furiously behind his zipper.

“Fuck,” he rasped; that was the last of his self control out the window. He’d waited long enough, it was his turn.

Zim cried out again when Dib withdrew, whole body squirming and shaking at the loss, Dib’s entire hand absolutely soaked to the wrist with Zim’s fluids, getting it all over his clothes as he pulled the hem of his shirt up to get to the fastenings of his pants.

“I’m fucking you,” he found himself babbling, trembling fingers struggling with the button on his jeans. “I’m fucking you so hard, Zim, I want you to remember how it felt to have me inside you for a fucking _week_.”

Zim was half out of it, he could tell; eyes glazed and heavy-lidded, sweating and squirming like his body had no clue how to process everything. It probably didn't.

Dib finally managed the zipper of his jeans, raising his hips to shove them down to mid-thigh, his cock springing up hard enough that his eyes almost teared with relief. Then all he needed was to get his knees under him, shifting and turning to face Zim fully before pulling the Irken into his lap by the hips.

Fucking _hell_ Zim's opening was wet enough that just pushing the tip of his cock inside made a gush of slick drip down his length, and the science part of his brain was apparently still functional enough to reassess a possible reason why; it had occurred to him that this could be an Irken version of an asshole, yes, but the more likely reason for all this lubrication suddenly smacked him upside the head—this was the Irken version of a _cunt_. Zim had fucking _both_.

"Holy shit," he gasped, both at the realization and the sensation, Zim's channel squeezing and spasming as Dib slid inside with hardly any effort. "Holy shit, holy _fuck."_

He could barely hear Zim's panted whines, could barely feel his claws digging into the backs of Dib's hands where he was gripping Zim's hips; all he could feel was the tight, wet heat around his dick and the squeeze of the Irken's legs around his waist.

He had no clue how he didn't lose it right then and there; it felt like he had been hard and on edge for hours, desperate and aching in his jeans, but somehow he found the motor skills to move—barely withdrawing, short, abrupt hitches of his hips inside Zim's body that jolted them both.

It was a blur; sensation and heat, Zim's noises a hazy background sound but the dig of his hands along Dib's arms sharp and clear, even through the fabric of his coat.

He didn't realize his gaze had fixated on Zim's squirming, dripping cock until Zim lurched up, grabbing two fistfuls of Dib's coat again and yanking him down. Dib did not have the coordination to catch himself, his hands still gripping tight to Zim's hips, so there was no grace to the way he fell forward—heavily, and with a startled gasp that turned into a shout when Zim's arms wrapped tight around his shoulders and his blunt teeth sank into Dib's neck.

They hurt each other all the time; they'd been hurting each other since the day they met, with fists and feet and weapons. But the gut-punch of this—of a hurt that didn't hurt but felt _so fucking good_ —immediately made him lose it, jerking in hard with another shout.

Zim's answering cry was muffled by his mouthful of Dib's neck, his hips grinding up and that slippery, prehensile cock between his legs rubbing hard against Dib's belly as Dib shuddered and gasped through the hard pulses of the most intense orgasm he had ever had.

 _"You wretched—"_ he heard Zim gasp, the insult cut off when suddenly, _astoundingly_ , Zim was coming again, just as messy and noisy as the first time—except now Dib got to feel it from _inside_ Zim's body and it was quite possible that his brain was going to implode.

He had never felt anything like it; not that he had anything to compare it to, but he couldn't _imagine_ that humans felt like this. That the muscles contracted in this rippling, milking pulsation, clamping down at the entrance so impossibly tight Dib saw stars. It was too much, his pelvis spasming in a final hard squeeze before his whole body went uselessly limp.

Of course Zim wasn't done; still squeezing and spasming, still pumping spurts of that thin clear cum between them, antennae twitching like mad against the side of Dib's head, in his hair. It was overwhelming, it was almost painful, and Dib grit his teeth as he tried to withdraw.

The noise of distress Zim made shocked him, freezing him in place as the Irken's arms and legs went painfully tight around him, keeping Dib inside and the two of them flush against each other.

"Zim," he gasped, digging the tips of his fingers into Zim's hips, trying to withdraw again when another rippling squeeze of Zim's pussy sent an overwhelming jolt through his nervous system.

He realized he _couldn't_ —Zim was too tight, the muscles at his entrance gripping and drawing him deeper in every time he tried to withdraw—at about the same moment that Zim literally _growled_ at him, sinking his teeth back into Dib's neck until he went still.

"Fuck," Dib breathed out shakily. It was about all he _could_ do, forced to ride out Zim's orgasm with him for however long it was going to take.

He let his forehead press into the cushion under them, just trying to breathe through each rolling wave of Zim's muscles clenching and his cock pulsing, until Zim's teeth finally released his throat in favor of a swirling lick of his tongue against Dib's rapid pulse, his climax seemingly starting to wane.

 _"Ungh,_ I hate you," Zim rasped against his neck, shivering through a fluttery squeeze of his inner muscles that made Dib grit his teeth and groan. "You wretched _worm,_ how _dare you_ dump your disgusting _fluids_ inside me!"

The side of Zim's fist thumped against Dib's shoulder, though there was hardly enough strength in it for Dib to even feel the impact; a fact that he took pride in as a result of the _two, thank you very much_ orgasms Zim had just experienced.

"Speak for yourself," Dib mumbled. "You're the one who's made a mess of the couch."

"The couch can be cleaned, I have your _revolting, inferior_ human genetic material inside me, it's completely different!"

As usual, Zim just had to phrase it in one of the weirdest ways possible, making Dib grimace. "You're the one with the weird, alien, steel trap pussy that won't let me go."

"I did not—!" Whatever Zim was going to say, he stopped himself with an audible click of his jaw, most certainly fuming at what Dib has just pointed out. "That is an involuntary reaction. I cannot be held responsible."

"Well you could have warned me!"

Zim bit his neck again with another annoyed growl, only now it didn't feel as good; the rush of arousal starting to fade, his pain perception readjusting, making Dib wince and huff out a growl of his own.

"Goddamnit, Zim!" He finally released Zim's hips, getting his elbows under him so he could pull back enough to look at the Irken with a proper glare of annoyance. Zim glared back, antennae still twitchy and skin clearly damp with perspiration, which suddenly made Dib very clearly aware of how wet with sweat he himself was under his coat and t-shirt. He really should have shed at least the coat for this.

But that wasn't what really caught his attention and stuck; it was the fact that Dib hadn't spent literally half his life obsessively watching and observing Zim to not know by now how to read him, and right now Zim's glare was more unease than actual irritation. It made him stop to think, mentally walking back everything they had just done for the source of Zim's uncertainty.

"Hey, wait a second!" Zim's eyes widened at Dib's exclamation. "You didn't warn me because you didn't know, did you?"

Zim's unease snapped to panic in a heartbeat, though he tried very hard to bluff his way through it. "What?! Preposterous! Zim knows everything!"

"No, no you didn't!" Dib insisted, thinking back even more. "You... you didn't even know that was there, did you? That's why it freaked you out so much when I fingered you, you had no idea you even had that! How could you not know?!"

"Shut up!" Zim's hands pushed on the front of his shoulders, his mouth curling into a snarl. "Shut your stupid mouth, Dib-filth! Get off! Get off of Zim!"

Zim pushed at him some more, heels kicking at the sides of Dib's hips, but very abruptly stopped when Dib tried again to withdraw and was met with a resistant spasm and clench of Zim's channel that made them both wince.

"I would ask how long this usually lasts, but clearly you don't know," Dib said dryly, settling back down again on his elbows to wait it out and trying to ignore the fact that his dick was most definitely capable of another round if they were stuck together much longer.

"Shut _up_ ," Zim growled again.

"Seriously though," Dib said thoughtfully. "Did you just... never have Irken sex ed? Is that not a thing your people do?"

"No," Zim said flatly. "My people do not rely on copulation for reproduction so there is no need."

"Really?" Dib asked curiously. "What do you do?"

Zim eyed him, seemingly weighing whether it would be dangerous for Dib to be informed of such information.

"Cloning, mostly." He finally said, apparently deciding that their distance from Irk would mediate any threat Dib could pose by his understanding. "Only the genetics of the finest Irk has to offer are spliced and cloned in our smeeteries, ensuring our _vast_ superiority continues." If Zim had a nose he would most certainly be turning it up in self-assured confidence.

Dib, meanwhile, was filing all this information away in his head for later note-taking.

"So Irkens don't usually have sex."

"No."

"But you decided to."

Zim looked at him with narrowed eyes. "I'm an invader. I can do whatever I want."

"And what you wanted was to have sex with me."

Zim gave him a flat, irritated look. "Don't let it go to your head, Dib-worm, it's too big as it is. You were merely... convenient."

Somehow, Dib didn't quite believe that. Not when Zim was so outwardly (and verbally) disgusted by most aspects of humanity. No, this most certainly had nothing to do with the fact that the two of them were an island, detached from all the other beings on earth with no one but each other to know the truth. Of _course_ it wasn't that.

"Uh-huh," was all Dib said, raising an eyebrow that was sure to make Zim annoyed with him.

"Shut up," Zim said again.

All told, it took about ten minutes for Zim's body to relax post-orgasm, finally allowing Dib to pull out and sit back, putting his feet back on the floor and letting his head rest on the back of the couch. He was a mess, they both were a mess, sweaty and covered in primarily Zim's fluids. He was definitely going to take a sample from his clothes to analyze later.

"Get out," Zim said eventually, pushing at Dib's thigh with his foot, still mostly undressed and on his back on the couch; he had tugged his tunic back down and that was about it. "Or I'm letting GIR eat you."

Somehow he didn't doubt that the weird little robot was not above trying such a feat; and besides, he wanted to go home and get clean anyway, not to mention get started analyzing Zim's genetic material.

"See you next time, Zim," he said, rising from the couch to leave.

"Absolutely not," Zim scoffed. "This will never happen again, Dib-filth."

The bite on his neck said otherwise. "Sure, Zim."

**Author's Note:**

> Man I have so many headcanons about Irken reproductive organs and someday I'll actually write a fic that incorporates them all. In the meantime find me [here.](https://my-squeedily-spooch.tumblr.com)


End file.
